Near infrared light technology supports scientists to measure adaptation potential of forest tree populations

| by Philippe Rozenberg

Forgenius is developing Near Infra-Red (NIR) calibrations to indirectly measure complex traits, such as vulnerability to drought, on a large number of trees, overcoming the scarcity of costly laboratory equipment.

Measuring selected phenotypic traits on a large number of trees is fundamental to understanding forests’ adaptation potential. Phenotypic traits are selected characteristics describing trees’ ability to survive, grow, respond and reproduce under changing climatic conditions. Once assessed, such phenotypic traits are then associated to genotypic values and environmental variables to estimate the potential of adaptation of forest tree populations to climate.

A high number of measurements are needed for an accurate estimate of adaptation potential. Some of these traits can be directly and easily measured in the field while others require sample collection and time-consuming operation with rare and costly laboratory equipment.

The scarcity of this laboratory equipment and high operation costs make it nearly impossible to measure these traits on the large number of trees needed. To overcome this difficulty, Forgenius is developing Near Infra-Red (NIR) calibrations for the complex traits. Samples which are used to measure the complex traits (leaves, branches, wood samples) are also submitted to NIR spectroscopy analysis: they are illuminated with a broad-spectrum of near infrared light, which can be absorbed, transmitted, reflected or scattered by the plant tissue. The near infrared light intensity is measured before and after interacting with the sample, and the corresponding signal is recorded and analyzed.

When the analysis is successful, a relationship between the complex trait and the Near Infra-Red Spectroscopy (NIRS) signal is revealed. We succeeded to develop good quality NIRS calibrations for several of the project complex traits. For example, we developed an accurate calibration for vulnerability to calibration (a proxy of resistance to drought) in black poplar (Populus nigra). These calibrations will be used to measure indirectly the complex traits on a much larger number of trees than is possible with standard laboratory method.

Want to know more? Read the full report on the work so far!

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